Three British citizens have been found guilty of plotting to kill thousands of people by blowing up transatlantic aircraft in mid flight.Abdulla Ahmed Ali, 28, Tanvir Hussain, 28, and Assad Sarwar, 29, were convicted at Woolwich Crown Court. Bombs containing liquid explosives were to have been used in the suicide attacks. Four other men were found not guilty of the plot. The bombers had intended to destroy at least seven airliners simultaneously, as they flew between London and the US and Canada. Each of the planes would carry an average of 250 passengers. The conspirators were arrested following the biggest surveillance operation carried out by British police. Prosecutors say the explosives were to have been hidden in soft drinks bottles. The suspected al Qaeda plot led to tight worldwide restrictions on the amount of liquids passengers could take on board flights.